NASA has yet to release its unprecedented Twin Study, which probes the genetic differences between astronaut Scott Kelly, who spent almost a consecutive year in space, and his identical twin Mark. 

Now, early findings indicate that life in space dramatically changes human biology, including gene expression. Measurements from before, during and after Kelly's mission at the International Space Station already reveal alterations in a wealth of biological markers. 

Identical Twins In Space

“[A]lmost everyone is reporting that we see differences,” said geneticist Christopher Mason from Weill Cornell Medicine in a Nature report. He said data are so brand new that some are still coming off their sequencing machines.

Mason and other scientists reported the early findings on Thursday, Jan. 26, delving on data ranging from the chromosomes to the gut microbiome of the twin brothers. Scott spent 340 days in orbit from 2015 to 2016 and has a lifetime total of 520 says, while Mark stayed in space for 54 days in four space shuttle missions from 2001 to 2011.

The brothers have nearly identical genomes and similar life experiences, so NASA is observing biological changes caused by extended stays in microgravity.

Upon Scott’s recent return to the planet, for instance, scientists discovered that his telomeres, the protective caps on each DNA strand, were longer than Mark’s. His telomeres have already returned to their usual length before the space mission, but researchers are studying how space travel may have caused them to lengthen.

In space, too, Scott underwent less DNA methylation, or when chemical markers are added to DNA for affecting gene expression. In contrast, his brother had an increase during his time, something that puzzles scientists.

Further, the team documented changes in genetic expression between the twins that normally happen in humans but appear more pronounced in Scott. This was probably because of consuming freeze-dried foods, sleeping while afloat in space, and similar stresses in long-haul spaceflight.

Rich Mine Of Genetic Data

NASA remains eager to know the effects of extended stays in orbit, as it currently works toward its manned Mars mission in the 2030s. For one, it might find its genetic tests useful for screening candidate astronauts for susceptibility to cancer.

The Twin Study’s official results may take time, with the Kelly brothers reviewing the data beforehand for any sensitive information they may wish to keep in privacy. In March 2016, the space agency said the first peer-reviewed study from the experiment may not come out for a year or two.

A round-trip mission to Mars is expected to last more than a year, with astronauts likely to spend lots of time in weightless surroundings.

Just recently, a team of six scientists — four men and two women — entered an isolated geodesic dome on a remote Hawaii volcano and are expected to spend the next eight months living there. This is done as part of human behavior research that could help in long-term space exploration, including NASA’s planned Mars journey.

During the eight months, the team will have no physical contact with the outside world and will experience a 20-minute lag in communications, the same period it would take for an email to get from the Red Planet to Earth. They will then be assessed for psychological conditions resulting from isolation and confined living.